Explosive projectile

ABSTRACT

An explosive projectile such as a grenade for firing from a mortar comprises an annular plastic body surrounding an explosive charge with the outer surface of the plastic body forming a part of the external surface of the projectile. The plastic body includes fragments embedded therein, and a fibrous material either randomly oriented or in the form of a net is embedded in the material of the plastic body adjacent the external surface. Optionally, a ring member having guide elements on the external surface thereof may be embedded in the external surface of the plastic body.

United States Patent 1191 Frostig 1 1 May 13, 1975 l l EXPLOSIVE PROJECTILE [75] Inventor: Amos Frostig, Haifa, Israel [73] Assignee: Etablissement Salgad, Vaduz,

Liechtenstein 221 Filed: Mar. 21, 1973 [21] Appl. No.: 343.317

617,519 4/1961 v Canada 102/64 1,237,195 6/1960 France 102/67 1,930,326 1/1970 Germany 102/491 Primary Ii.mnziner-Verlin R. Pendegrass Attorney, Agent, or FirmMarkva & Smith 1571 ABSTRACT An explosive projectile such as a grenade for firing from a mortar comprises an annular plastic body surrounding an explosive charge with the outer surface of v the plastic body forming a part of the external surface of the projectile. The plastic body includes fragments embedded therein, and a fibrous material either randomly oriented or in the form of a net is embedded in the material of the plastic body adjacent the external surface. Optionally, a ring member having guide elements on the external surface thereof may be embed- I ded in the external surface of the plastic body.

1 Claim, 2 Drawing Figures 1 i EXPLOSIVE PROJECTILE The present invention relates to an explosive projectile and more particularly to an explosive projectile which includes a plurality of fragments such as balls or other metallic pieces embedded in a plastic material surrounding the explosive charge.

Various types of projectiles are known wherein fragments are positioned about an explosive Charge, the fragments being contained within an outer casing or sleeve, usually of metal. In such an arrangement, the thickness of the wall of the outer casing is substantial so that the metal casing severely reduces the range of the fragments propelled by the explosion as the fragments must be driven through the metal casing. Part of the kinetic energy is absorbed in shattering and breaking up the casing.

An object of the present invention is to provide a projectile in which the fragments. are located about the explosive charge but in which the construction of the projectile is such that the resistance to the projected fragments at the time of explosion is negligible.

Briefly, in accordance with the present invention, the explosive charge is contained within a generally tubular steel casing. Surrounding the casing is a body of plastic material in which the fragments are embedded, the external surface of the plastic body forming at least a part of the outer surface of the projectile. A continuous layer of a fiber fleece or the like is embedded in the plastic body adjacent the external surface thereof giving the plastic body the necessary strength, but at the same time offering only negligible resistance upon explosion.

The invention will now be described in greater detail with reference to the drawing in which:

FIG. 1 is a side view partly in cross-section of a mortar projectile according to the present invention; and

FIG. 2 is a partial cross-sectional view of another embodiment of the mortar projectile in accordance with the present invention.

The mortar projectile or grenade l is a fin-stabilized projectile comprising a main body 2, a forward transitional part 411 with a head ignitor 3, a rear transitional part 4!: and a tailpipe 5 with guide fins.

The projectile is provided with a preferably tubular inner member 6 of steel or aluminum containing an explosive charge 6'. Member 6 is connected to the forward and rear portions of the projectile in an appropriate manner, e.g., by screw connections. Fragments 7. which may be in the form of metal pieces. steel balls. and the like, are embedded in a body 8 of solid synthetic resin or the like, the fragments 7 being uniformly distributed in the resin mass. The plastic body 8 containing the fragments is formed as a unitary structure and may be composed of any of the well known synthetic resins such as vinyl chloride, polyethylene. etc. The external surface ofthe plastic body 8 forms the external surface of a portion of the projectile. A layer 9 of randomly oriented or woven fibers is advantageously provided at the outer surface. These fibers may comprise inorganic or synthetic substances or even a metal or the like. The layer. in the form of a fiber-fleece. is preferably embedded in the exterior surface ofthe plastic body 8 during the casting process. As an alternative to the fiber-fleece layer. a net can be used which is embedded adjacent the external surface of the plastic body 8. The net. like the fibers of the lleeee layer. may

comprise textiles, glass and/or metal. Guide elements such as annulargrooves or the like may be provided in the layer 9.

The fibrous fleece or net provided on the peripheral surface of the plastic body increases the mechanical strength of the projectile. This is important, particularly, where the external surface of the plastic body 8 is at the point of the largest diameter of the projectile where it will contact the interior surface of the mortar barrel when fired. The layer 8, however, is thin enough to offer little or no resistance to the acceleration of the fragments during detonation. The result is an explosive projectile in which the plastic body carrying the embedded fragments is effectively protected against accidental external damage without a reduction in the effectiveness of the kinetic energy in projecting the fragments at the time of detonation.

Optionally, as shown in'FIG. 2, a ring 10 of predetermined thickness can be embedded in the plastic body 8 or in the fibrous layer 9 in the region of the projectile having the largest diameter. The external surface of the ring 10 includes guide elements 11. It will be noted that the guide ring 10 forms an integral part of the plastic body 8. The fibrous layer 9 may or may not be included beneath the ring 10. The ring 10 may be formed from either a plastic or metal.

Instead of an independent ring 10, the region of maximum diameter of the projectile can simply be reinforced by one or more additional fibrous layers embedded in the plastic material with the guide elements 11, such as the annular grooves, directly in the surface of the plastic body 8.

The axial width of the ring 10 is relatively narrow so that it will not offer any appreciable resistance to the fragments upon detonation. If the ring 10 is produced from a plastic material or if. instead of the ring. an additional reinforcing layer of fibers is utilized. the possibility of impairing the projection of the fragments is even further reduced.

The plastic body 8 is preferably molded directly onto the inner steel casing 6 such that there is little possibility of the plastic body separating from the inner casing containing the explosive charge 6. Alternatively. the plastic body 8 may be molded separately and then pressed on the steel casing 8 such that it tightly fits about the steel casing.

The plastic body may have a cylindrical. pointed. arcuatc or toricouter contour when used in a mortar grenade. However. such plastic bodies with the embedded fragments may also be utilized in other types of projectiles such as bombs. land mines and the like. In such instances the plastic body may be in the form of a disc. a thick ring. a hollow prism or the like having any type of external contour. Optionally. the plastic body can be produced in the form of a plurality of interfitting parts which may be secured together to form an assembly about the explosive charge. The explosive projectile as described above permits the fragments to be projected over a substantially greater area upon detonation. The plastic body which is not confined in an outer casing offers practically no resistance to the dispersal or scattering of the fragments upon detonation resulting in substantially improved coverage by the fragments. The plastic body disintegrates under the force of the detonation permitting optimal transformation of the force into kinetic energy in the fragments.

I claim:

l. A fin-stabilized projectile consisting essentially of a. a frame structure including an elongated metallic tubular member, a conical head portion secured to one end of said tubular member and a cylindrical tail portion having a plurality of radially projecting fins and secured to the opposite end of said tubular member, the diameters of said head and tail portions adjacent said tubular member being greater than the cross-section of said tubular member;

b. an explosive charge in the interior of said tubular member;

c. an annular solid body surrounding and being secured to said tubular member and extending between said head and tail portions, the circumferential surface of said body at the opposite ends thereof having substantially the same diameter as the adjacent parts of said head and tail portions respectively, and a portion of the circumferential surface spaced from and intermediate the ends of said body having a greater diameter than either end thereof and a greater diameter than the radial length of said fins from the axis of said tail portion,

4 said annular body comprising a multiplicity of fragments uniformly distributed and embedded in a synthetic resin;

(1. a protective, thin, fibrous, reinforcing, porous, net

web embedded in the surface of said annular body, the composition of said web being selected from the group consisting of textile, glass and metal; and

. said intermediate portion of said body having a said synthetic resin of said body and said thin p0 rous web giving no appreciable resistance and the axial length of said ring member being insufficient to give appreciable resistance to acceleration of said fragments following detonation of said explosive charge. 

1. A FIN-STABILIZED PROJECTILE CONSISTING ESSENTIALLY OF A. A FRAME STRUCTRUE INCLUDING AN ELONGATED METALLIC TUBULAR MEMBER, A CONICAL HEAD PORTION SECURED TO ONE END OF SAID TUBULAR MEMBER AND A CYLINDRICAL TAIL PORTION HAVING A PLURALITY OF RADICALLY PROJECTING FINS AND SECURED TO THE OPPOSITE END OF SAID TUBULAR MEMBER, THE DIAMETERS OF SAID HEAD AND TAIL PORTIONS ADJACENT SAID TUBULAR MEMBER BEING GREATER THAN THE CROSS-SECTION OF SAID TUBULAR MEMBER; B. AN EXPLOSIVE CHARGE IN THE INTERIOR OF SAID TUBULR MEMBER; C. AN ANNULAR SOLID BODY SURROUNDING AND BEING SECURED TO SAID TUBULAR MEMBER AND EXTENDING BETWEEN SAID HEAD AND TAIL PORTIONS, THE CIRCUMFERENTIAL SURFACE OF SAID BODY AT THE OPPOSITE ENDS THEREOF HAVING SUBSTANTIALLY THE SAME DIAMETER AS THE ADJACENT PARTS OF SAID HAD AND TAIL PROTIONS RESPECTIVELY, AND A PROTION OF THE CIRCUMFERENTIAL SURFACE SPACED FROM AND INTERMEDIATE THE ENDS OF SAID BODY HAVING A GREATER DIAMETER THAN EITHER END THEREOF AND A GREATER DIAMETER THAN THE RADIAL LENGTH OF SAID FINS FROM THE AXIS OF SAID TAIL PORTION, SAID ANNULAR BODY COMPRISING A MULTIPLICITY OF FRAGMENTS UNIFORMLY DISTRIBUTED AND EMBEDDED IN A SYNTHETIC RESIN; D. A PROTECTIVE, THIN, FIBROUS, REINFORCING, POROUS, NET WEB BEDDED IN THE SURFACE OF SAID ANNULAR BODY, THE COMPOSITION OF SAID WEB BEING SELECTED FROM THE GROUP CONSISTING O SISTING OF TEXTILE, GLASS AND METAL; AND E. SAID INTERMEDIATE PORTION OF SAID BODY, SAIID ANNULAR RING DIAMETER COMPRISING A NARROW ANNULAR RING MEMBER EMBEDDED IN THE SURFACE OF SAID BODY, SAID ANNULAR RING MEMBER BEING SELECTED FROM THE GROUP CONSISTING OF METAL AND PLASTIC AND INCLUDING A PLURALITY OF ANNULAR GROOVES IN THE CIRCUMFERENTIAL SURFACE THEREOF PROVIDING GUIDE ELEMENTS FOR SAID PROJECTILE; F. SAID SYNTHETIC RESIN OF SAID BODY AND SAID THIN POROUS WEB GIVING NO APPRECIABLE RESISTANCE AND THE AXIAL LENGTH OF SAID RING MEMBER BEING INSUFFICIENT TO GIVE APPRECIABLE RESISTANCE TO ACCELERATION OF SAID FRAGMENTS FOLLOWING DETONATION OF SAID EXPLSOIVE CHARGE. 